Oscillatory-rotary liquid dispensing device with spring, and associated method

ABSTRACT

The present invention relates to a device for dispensing liquid product, comprising a fixed part and a moving part; the fixed part comprising an intake orifice, a delivery orifice, a body comprising a cavity into which said orifices open, said cavity being able to partially house the moving part, the remaining volume forming an emptying chamber; the moving part being able to move partially in the cavity of the fixed part and comprising a piston, a piston driving element, an axial spring, a duct extending along the circumference of the piston, said duct allowing positions that allow fluidic communication between the emptying chamber and just one of said orifices and allowing switchover positions in which all fluidic communication between the emptying chamber and each of said orifices is forbidden, a cam able to convert the rotation of the drive element into an oscillatory-rotary movement of the piston. The axial spring is able to absorb energy during a liquid intake phase and to restore same during a liquid delivery phase, said spring being positioned around the piston which is on the moving part situated inside the cavity of the body.

FIELD OF THE INVENTION

The present invention relates to an oscillatory-rotary volumetricsubassembly and to a device for volumetric pumping of a fluid.

PRIOR ART

The use of volumetric pumping devices for delivering (injection,infusion, oral, spraying.) fluids and/or powder is known, notably formedical, aesthetic, veterinary or food applications. In particular, inthe medical field, different mechanical or electromechanical systems areknown, subassemblies such as “syringe pump,” “cartridge pump devices,”peristaltic pumps, piston pumps, rotary pumps. In the case of pumpsactuated by a motor, whether it is linear or rotary, when the fluid isto be transferred at a high speed and a high pressure, that is to sayhigher than 4 bar, this entails the use of a motor allowing one tooperate at a high speed and capable of supplying a high force or a hightorque.

In this field, the application EP1803934 is known, which relates to apump including a stator, a rotor including an axial extension whichslides and rotates at least partially in a rotor chamber of the stator,and at least first and second valves between an inlet and a rotorchamber, respectively between the rotor chamber and an outlet, whichopen and close as a function at least of the angular movement of therotor. The pump includes cam elements interacting on the rotor and thestator and biasing means acting on the rotor in order to apply a forceto the rotor in the axial direction of the stator cam element.

This prior art represented an insufficient advance for reducing the sizeof the oscillatory-rotary pump motors for integration in a portabledevice.

Also known is patent EP3025058A1 which describes an oscillatory-rotarysubassembly for volumetric pumping of a fluid, which comprises a hollowbody defining a cavity whose wall is passed through by two ducts, thepiston defining with said cavity a working chamber and comprising agroove opening longitudinally into said working chamber, said pistonbeing angularly movable in order to put said working chamber in fluidiccommunication with one and then none and then the other of said ducts,and alternately in longitudinal translation so as to vary the volume ofsaid working chamber and then successively deliver said fluid, saidpiston bearing a sealing gasket formed by at least one sealing ring, asealing half-ring and at least one sealing strip longitudinallyconnecting said sealing ring to said sealing half-ring.

Although this pump can be designed for small swept volumes and canwithstand high pressures, it is necessary to use a very high rotationspeed of the motor when one wishes to quickly administer a fluid.Moreover, in order to achieve this rotation speed, the acceleration timeof the motor is not negligible with respect to the duration of ejectionof the fluid dose delivered by the pump. The result is that the ejectionspeed is not constant in the course of the dose. This leads to motors ofrelatively large size for integration in a portable device.

Also known is patent EP2962714 which describes a micropump using aneccentric cam element which turns in a pump casing in order tosequentially open and close valves in the pump casing in order towithdraw the fluid from a reservoir and supply measured quantities ofthe fluid to a cannula orifice for administration to a patient. Themicropump can be used in a disposable pump for continuous perfusion ofdrugs such as insulin.

The eccentric cam sequentially biases each valve actuator during acomplete rotation of the piston. This prior art represented aninsufficient advance for pulsed administration of liquid with a motor ofsmall size. In addition, the restoring force on the sealing gasketsexerted by the valve springs has to be sufficiently high in order toensure that the valve actuators do not open under the operatingpressures of the micropump.

Other examples of volumetric pumping devices for delivering (injection,infusion, oral, spraying.) fluids and/or powder are also illustrated indocuments DE202004 018603, DE1936358, FR1416519, WO2015/011384,US1866217, US2005/132879, US4850824, FR940128 and FR1463091.

SUMMARY

The present invention was developed in order to solve the aforementionedproblems, in particular the ability to ensure ejection of product at aconstant speed for a duration which can be less than 100 ms whilereducing the size of the oscillatory-rotary pump motors in order toreduce their space requirement and ensure the miniaturization of thefinal device. In fact, the torque necessary to actuate a device of thetype according to the invention is high and requires the use of an oftenbulky motor having a high energy consumption and thus limiting theminiaturization.

The present invention thus relates to a device for dispensing product inliquid form, comprising a fixed part and a movable part, the fixed partincluding an intake orifice, a delivery orifice, a body comprising acavity into which said orifices open, said cavity being able topartially house the moving part, the volume formed between the surfaceof the cavity and the moving part defining an emptying chamber, themoving part being able to move partially in the cavity of the fixed partand including a piston, a piston driving element, an axial spring, aduct extending along the circumference of the piston, said duct on theone hand allowing positions that allow fluidic communication between theemptying chamber and just one of said orifices and on the other handallowing switchover positions in which all fluidic communication betweenthe emptying chamber and each of said orifices is forbidden, the deviceaccording to the invention including a cam able to convert the rotationof the driving element into an oscillatory-rotary movement of thepiston, characterized in that the axial spring is able to absorb energyduring a liquid intake phase and to restore same during a liquiddelivery phase, said spring being positioned around the piston which ison the moving part situated in the cavity of the body.

Preferably, the axial spring used in the present invention is a helicalspring in order to assist the motor in increasing the torque suppliedduring the delivery phase. Preferably, the helical spring can be takenaway from the action of the motor. Advantageously, the helical springallows simplicity of assembly.

In the present invention, the duct extending along the circumference ofthe piston is delimited by sealing lips in order to ensure thefluid-tightness between the piston and the body of the device, as wellas between the different fluid circulation zones.

Preferably, said duct includes a delivery groove connecting the deliveryorifice to the emptying chamber during the delivery phase and an intakegroove connecting the intake orifice to the emptying chamber during theintake phase, said grooves being implemented so as to alternately putone of the orifices, the intake orifice or the delivery orifice, influidic communication with the emptying chamber or forbid any fluidiccommunication between said orifices and the emptying chamber during therotation.

In one embodiment of the invention, the intake groove is in the form ofa helical internal threading forming an angle α preferably identical tothe angle of the slope of the cam in order to reduce the dead volume.

Preferably, the delivery groove extends on an axis co-linear with thatof the cam abutment and forms with the longitudinal axis of the pistonan angle β such that 0° ≤ β ≤ 70°, this in order to optimize theoperation of the device during the delivery step.

Also preferably, the angle β is an angle of 0°.

In another embodiment, the intake orifice and the delivery orifice areangularly separated by an angle between 170° and 190° on a planeperpendicular to the longitudinal axis of the piston (22) in order tosimplify the design of the sealing gasket taking into consideration itsoptimal moldability. Preferably, the intake orifice and the deliveryorifice are substantially at 180° with respect to one another on thissame plane.

The present invention also relates to a method for administering afluid, including four successive steps. During a first intake step, thedevice according to the invention is actuated to drive the rotation ofthe cam in order to obtain an oscillatory-rotary movement of the piston,and during said oscillatory-rotary movement, the intake orifice is incommunication with the duct, and the delivery orifice is covered so asto obtain the filling of the emptying chamber and the compression of theaxial spring between the cam and a spring support. During a firstintermediate step, also referred to as maximum switchover step, afterthe intake step, the two orifices, the intake orifice and deliveryorifice, are covered and non-communicating, and during which theemptying chamber is in its maximum volume. During a third delivery step,the axial spring is decompressed in order to bring about the translationof the piston, in order to empty the emptying chamber through thedelivery groove in fluidic communication with the delivery orifice.During a second intermediate step, also referred to as minimumswitchover step, the two orifices, the intake orifice and the deliveryorifice, are covered and non-communicating and the piston is at the endof the stroke in the cavity of the body of the fixed part, and the axialspring is released.

Preferably, the height of the abutment of the cam is adjustable in orderto vary the volume of liquid ejected from the emptying chamber throughthe delivery orifice. This makes it possible to vary the amplitude andadjust the maximum volume.

The present invention also relates to any medical apparatus containingthe device described here or using the method for administering liquiddescribed here.

The present invention also relates to a fluid cartridge including afluid circuit and a dispensing device according to the invention.

DEFINITIONS

In the present invention, the terms below are defined as follows:

-   “inner threading angle α” relates to the tilt of the helical intake    groove with respect to the axis of the piston.-   “duct” indicates the path travelled by the liquid; in the preferred    embodiment, it involves an intake groove having the form of a    helical inner threading and a delivery groove, the two grooves being    situated on the periphery of the piston-   “substantially” in the context of the invention means that one is    within the margin of error corresponding to the precision of the    tool for measuring the value.-   “fluid,” in the invention, the fluid is a gas or a liquid, it is    preferably a liquid.-   “Cartridge:” Detachable casing capable of including a fluid    dispensing device.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a longitudinal section of the device according to theinvention, wherein the piston is at the end of the stroke in the cavityof the body of the fixed part, the chamber is emptied, and the axialspring is released (minimum switchover step).

FIG. 2 is a perspective view of the device according to the invention,wherein the piston is at the end of the stroke in the cavity of the bodyof the fixed part, the chamber is emptied and the axial spring isreleased (minimum switchover step). The cam support of the fixed part isnot illustrated.

FIG. 3 is a longitudinal section of the assembly consisting of the bodyof the fixed part, of the cam, of the piston, of the spring, of thesealing gasket and of the orifices, when the piston is at the end of thestroke and the emptying chamber is emptied (minimum switchover step).

FIG. 4 is a front view of the assembly consisting of cam, piston,sealing gasket and duct, when the piston is at the end of the stroke andthe emptying chamber is emptied (minimum switchover step).

FIG. 5 is a perspective view of the assembly illustrated in FIG. 4 ,wherein the emptying chamber is filled with a liquid product. Thisfigure is a perspective view of the assembly consisting of cam, piston,sealing gasket and duct.

FIGS. 7 a, 7 b, 7 c and 7 d illustrate the development of thecylindrical peripheral surface defined by the sealing gasket and thesealing lips. These four figures show the configurations of the intakeand delivery orifices as a function of the intake and delivery groovesduring the four operational steps of the device.

FIG. 6 is a longitudinal section of the device according to theinvention, wherein the emptying chamber is filled with liquid and theaxial spring is compressed.

FIGS. 7 e, 7 f, 7 g and 7 h illustrate the development of the outerperipheral surface of the cam. These four figures show theconfigurations of the cam as a function of the cam support during thefour operational steps of the device.

FIGS. 8 a to 8 d are front views of the assembly including the end ofthe piston and the sealing gasket, illustrating four differentconfigurations of the assembly during a complete rotation of the movingpart, in which the delivery orifice is represented in a projected view.

FIGS. 8 e to 8 h are front views of the assembly including the end ofthe piston and the sealing gasket, which show the opposite side fromthat illustrated in FIGS. 8 a to 8 d , respectively, and wherein theintake orifice is represented in a projected view.

DETAILED DESCRIPTION

The present invention relates to a device for dispensing liquid productand will be understood better upon reading the following figures whichare an illustration without any intention of limiting the invention.

As detailed in FIG. 1 , the body 13 of the fixed part 1 is hollow andcomprises at least two cylindrical cavities 151, 152 having longitudinalaxis (A) and different diameters, which are connected to one another bya shoulder 18 and communicate with one another thus defining the cavity15 which is able to house the moving part 2. The cylindrical cavity 152of large diameter communicates with the outside as well as with thecylindrical cavity of small diameter 151; this cavity is configured topartially house a spring support 16 and to completely house the helicalspring 23 and the cam 25. It should be noted that the coils of thehelical spring 23 are wound around the moving part 2; this spring restson the spring support 16 which constrains it during the intake phase.The release of the spring 23 makes it possible to provide additionalenergy to the motor for moving the piston 22 in order to empty theemptying chamber 27.

As can be seen in FIG. 1 , the spring 23 is positioned around the piston22. Having the spring around the piston 22 provides a reinforcedstability to the device. In fact, depending on the dimensioning and thestiffness of the selected spring 23, it is possible that a bucklingphenomenon of the spring 23 is observed during its compression. Thecentering around the piston 22 makes it possible to avoid this problem.Advantageously, this configuration moreover allows a simplicity ofassembly and a greater compactness by capitalizing on the presence ofthe bearing surface between the spring support 16 (pump body) and thepiston 22. The centering of the spring 23 around the piston 22 has yetother advantages such as the placement and the centering of the meansfor reducing frictional forces between the spring 23 of the bearingsurfaces. Generally, the centering of the spring 23 in axial positionallows a better distribution of the mechanical stresses on the piston22.

In a preferred embodiment, the release of the spring makes it possibleto provide energy necessary for moving the piston in order to empty theemptying chamber 27. In FIG. 1 , this makes it possible to move thepiston 22 and to empty the emptying chamber 27. This makes it possibleto reduce the necessary torque of the latter and thus to reduce its sizeand its space requirement.

Moreover, the cam 25 comprises an inclined ramp 251 which is able toslide on a cam support 14 of the fixed part 1. The small-diametercylindrical cavity 151 has an end communicating with the large-diametercylindrical cavity 152, and a closed end. The cylindrical cavity 151 isintended to partially house the piston 22. The sealing between thepiston and the small-diameter cylindrical cavity 151 is provided by thepiston sealing gasket 29. The cylindrical cavity 152 can have, forexample, a variable diameter in order to adapt to the spring support 16and to the piston driving element 21.

In reference to FIG. 2 , the piston driving element 21 is a cylinderwith longitudinal axis A, having a form suitable for housing a motor,comprising, for example, a flat section and a cylindrical cavity; it isconnected to the moving part 2 via a connection means 30; saidconnection means 30 can be of any form complementary to thecorresponding recess located in the piston 22; a flat or cross-shapedform can be considered, for example. The piston driving element 21 canbe driven preferably by a motor, but any other means for providingmechanical energy can be considered. It is specified that this elementis preferably driven by a motor, but any other means of supplyingmechanical energy can be considered, keeping in mind that the presenceof the axial spring will make it possible to reduce the required energycontribution. This is true provided that the means for supplying energyhas sufficient impulse.

In reference to FIG. 3 , the sealing gasket 29 and the duct 24 areimplemented so as to alternately, that is to say successively one afterthe other with possibility of intermediate steps, put one of theorifices, namely the intake orifice 11 or the delivery orifice 12,respectively, in fluidic communication with the emptying chamber orforbid any communication between the intake or delivery orifices 11, 12,respectively, and the emptying chamber 27. In the example illustrated inFIG. 3 , the delivery orifice 12 is in fluidic communication with theemptying chamber 27. Communication between the emptying chamber 27 andthe intake orifice 11 is forbidden. More particularly, the configurationof the duct 24 (visible in FIG. 4 ) and of the sealing gasket 29 allowsfluidic communication between one of the orifices, namely the intakeorifice 11 or the delivery orifice 12, and the emptying chamber duringthe intake and delivery steps; this is illustrated in FIGS. 7 a and 7 c, respectively. This configuration according to the invention forbidsany fluidic communication between the intake and delivery orifices 11,12, respectively, and the emptying chamber 27 during the intermediatesteps also referred to as switchover steps, which are illustrated byFIGS. 7 b and 7 d .

As illustrated by FIGS. 1 to 3 , the cavity 15 is put in fluidiccommunication with an upstream fluid circuit and a downstream fluidcircuit, and with the outside via the intake and delivery orifices 11,12 opening onto the outer surface of the body 13 and having an axis ofsymmetry perpendicular to the axis A. Each of the two orifices, namelythe intake orifice 11 and the delivery orifice 12, respectively, has acylindrical part of small diameter opening inside the cylindrical cavity151 and a portion of larger diameter opening outside of the body 13. Inthe example illustrated, the large-diameter portion of the deliveryorifice 12 thus has a frustoconical form and the small-diameter portionof the intake orifice 11 has cylindrical form. The axis of the intakeorifice 11 and the axis of the delivery orifice 12 can be offsetlongitudinally with respect to the axis A and angularly along a planeperpendicular to the axis A. In the example illustrated in FIGS. 1 and 3, the intake and delivery orifices 11, 12 are offset longitudinally withrespect to the axis A and are offset from one another by an angle of180° along a plane perpendicular to the axis A. In an alternativeembodiment (not illustrated), the two orifices, namely the intakeorifice 11 and the delivery orifice 12, are angularly offset from oneanother by an angle of 0°. In another alternative embodiment, they arenot longitudinally offset with respect to one another.

As detailed in FIG. 4 , the piston 22 has a diameter which is slightlysmaller than the diameter of the cylindrical cavity 151, and the sealingbetween the piston 22 and the body of the fixed part 1 is provided bythe compression of the sealing gasket 29 positioned on the end of thepiston 22. In particular, the sealing gasket 29 has a generallycylindrical form; the inner surface of said gasket is in close contactwith the outer surface of the piston 22, and the outer surface of saidgasket is provided with sealing lips 26 intended to be compressedagainst the surface of the cylindrical cavity 151 in order to ensure afluid-tightness of the duct and of the chamber.

As illustrated in FIGS. 4 and 5 , said sealing lips 26 define multiplechannels having different depths, namely at least one first channelhaving one end opening into the emptying chamber 27, at least one secondchannel in fluidic connection with said first channel, and additionalnon-communicating channels which are not in communication with theemptying chamber 27 and preferably having a depth which is less thanthat of the first channel and of the second channel, in order tominimize the dead volumes. As illustrated in FIG. 4 , the first channelopening into the emptying chamber 27 corresponds to the delivery groove241, the channel in fluidic connection with said first channelcorresponds to the intake groove 242, and said first channel and secondchannel form a duct 24 on the circumference of the gasket.

It should be noted that the duct 24 is entirely arranged on thecircumference of the gasket and in particular contains no portion insidethe piston 22. As illustrated in FIG. 4 and in FIGS. 7 a to 7 d , thesealing lips 26 also define additional non-communicating channels havinga depth less than that of the delivery and intake grooves and extendingaround the sealing gasket 29 in order to face one of the orifices,intake orifice 11 or delivery orifice 12 when the other orifice 12, 11is facing a delivery groove 241 or intake groove 242 of the duct 24 orfacing another additional channel.

More particularly, during an operational step of the device illustratedin FIG. 7 a , the intake orifice 11 faces the intake groove 242, and thedelivery orifice 12 is in one of said additional channels which are notin communication with the emptying chamber 27. In a second operationalstep illustrated by FIG. 7 b , the two orifices, the intake orifice 11and the delivery orifice 12, are in additional channels which are not incommunication with the emptying chamber 27. In a third operational stepof the device represented in FIG. 7 c , the delivery orifice 12 facesthe delivery groove 241, and the intake orifice 11 is in an additionalchannel which is not in communication with the emptying chamber 27.Advantageously, the width of the delivery groove 241 and of the intakegroove is substantially greater than the diameter of the intake anddelivery orifices 242. In FIG. 7 d , as in 7c, one orifice is coveredand the other is in the groove 241.

The duct 24 included on the sealing gasket 29 and delimited by thesealing lips 26 includes a delivery groove 241 forming an angle βbetween 0° and 70° with the axis A and an intake groove 242, forexample, in the form of a helical inner threading forming an angle αwith respect to the axis A. The angle β is defined in FIG. 4 and ispreferably an angle of 0°, and the angle α is identical to the angle ofthe slope of the cam 25. In this configuration (illustrated in FIG. 4 ),the delivery groove 241 is parallel to the axis A and extends in adirection included in the co-linear plane of the cam abutment 28. In analternative embodiment not represented, the delivery groove 241 and thecam abutment 28 form an angle β with the axis A, which is between 0° and70° while being different from 0°. Preferably, the delivery groove 241extends in a direction parallel to that of the extension of the camabutment 28. In the present case, the spring makes it possible tocontribute additional energy to the motor.

In reference to FIG. 5 , the position of the free end of the piston 22in the cavity 151 defines an emptying chamber 27 with cylindrical shapeand variable volume. The volume of the emptying chamber 27 is defined bythe inner volume of the cavity 151, extending from the closed end ofsaid cavity to the flat circular surface which is part of the free endof the piston 22. When the piston 22 is in its low position, the spring23 is compressed, the emptying chamber 27 is at its maximum volume(configuration visible in FIGS. 5 and 6 ), whereas, when the piston 22is in its high position, the spring is in its released position since itis returned to its initial position with reduced stress, the emptyingchamber is at its minimum volume (configuration visible in FIGS. 1 to 4), and the liquid has been expelled.

As detailed in FIGS. 1, 4 and 5 , the cam 25 comprises an inclined ramp251 (FIGS. 4 and 5 ) which is able to slide on a cam support 14 (FIG. 1), and a cam abutment 28 in the form of a step including a radialsurface with respect to the axis A and delimited by two parallel sides281 and 282 in common with the inclined ramp 251 of the cam 25. Inparticular, in reference to FIGS. 4 and 5 , the side 281 connects thecam abutment 28 to a high portion of the inclined ramp 251, and the side282 connects the cam abutment 28 to a low portion of the inclined ramp251. In practice, each side 281, 282 is the edge of a dihedral angleformed by the meeting of the cam abutment 28 with the inclined ramp 251.

It should be noted that the sealing gasket 29 can be manufactured, forexample, by overmolding on the piston 22 or manufactured independentlyof the piston and assembled thereon. The sealing gasket 29 is positionedaround the end of the piston 22 which is able to move in the cavity 151.

As illustrated in FIGS. 7 e, 7 f, 7 g and 7 h , the upper portion andthe lower portion defining the beginning and the end of the inclinedramp 251 are perpendicular to the axis A. Consequently, the dihedralangle formed by the meeting of the cam abutment 28 with the upperportion or the lower portion of the inclined ramp 251 is a right angleof 90°. The reversal of the direction of rotation of the moving part isprevented by the presence of the cam abutment 28. In an alternativeembodiment, not represented, the cam abutment 28 comprises a nonradialsurface with respect to the axis of the piston, which connects the upperportion to the lower portion of the inclined ramp 251 with an angle withrespect to the axis of the piston different from 90°. In thisalternative embodiment, the delivery groove 241 is inclined with respectto the axis of the piston with an angle β between 0° (excluded) and 70°,while being identical to the angle formed by the cam abutment 28 andsaid axis.

FIGS. 7 a to 7 d illustrate the development of the lateral surface ofthe cylinder defined by the sealing gasket 29; the small-diameterportions of the intake and delivery orifices 11 and 12 are representedin a view projected on a plane.

FIGS. 7 e to 7 h illustrate the development of the outer surface of thecam 25; the cam support 14 is represented in a view projected on aplane. For the sake of simplification and to facilitate understanding ofthe diagram, a simplified representation of the cam support 14 is shown.

The mode of operation of the device according to the preferredembodiment is as follows:

During the intake step, a motor drives the nearly complete rotation ofthe cam 25 in order to obtain an oscillatory-rotary movement of thepiston 22 in the cavity 15; during the oscillatory- rotary movement, thepiston 22 goes from a high position in which the emptying chamber has aminimum volume of liquid (FIGS. 1 to 3 ) to a low position (FIG. 5 ) inwhich the emptying chamber 27 is filled with liquid.

The step defined by the cam abutment 28 can alternately have a positionwhich is adjustable by a pin which is able to transmit kinetic energy tothe piston. Between the beginning of the intake step and the end of thedelivery step, the cam 25 has performed a complete rotation of 360°.

The pulsating decompression of the axial spring 23 during the deliverystep drives the translation of the piston 22 from a low position (FIGS.5 and 6 ) in which the emptying chamber 27 is suitable for being filledwith liquid to a high position (FIGS. 1 to 4 ) in which the emptyingchamber 27 is suitable for being emptied of liquid.

As illustrated in FIG. 7 c , during the delivery step, the intakeorifice 11 is covered in an additional channel which is not incommunication with the emptying chamber 27, and the delivery orifice 12is in fluidic communication with a delivery groove 241 which islongitudinal with respect to the axis A or oblique at an angle β between0° and 70°; in the example illustrated in FIGS. 7 a to 7 d and in FIGS.8 a to 8 d , the angle β is an angle of 0°. FIGS. 8 a, 8 b, 8 g, 8 hillustrate examples of configurations in which the intake orifice 11 orthe delivery orifice 12 is covered in an additional channel which is notin communication with the emptying chamber. It should be noted that thenon-communicating additional channels are exclusively used for providingthe sealing and the closing of the intake orifice 11 or the deliveryorifice 12 during the intermediate steps, also referred to as minimumand maximum switchover steps.

Reference Numerals

-   1: Fixed part-   11: Intake orifice-   12: Delivery orifice-   13: Body-   14: Cam support-   15: Cavity-   151, 152: Cylindrical cavities-   16: Spring support-   18: Shoulder-   2: Moving part-   21: Piston driving element-   22: Piston-   23: Axial spring-   24: Duct-   241 : Delivery groove-   242: Intake groove-   25: Cam-   251: inclined ramp-   26: Sealing lips-   27: Emptying chamber-   28: Cam abutment-   281, 282: Sides of the cam abutment-   29: Sealing gasket-   30: Connection means-   A: Axis of the piston-   D: Device-   α: Tilt angle of the helical intake groove with respect to the    longitudinal axis of the piston.-   β: Inclination angle of the delivery groove with respect to the    longitudinal axis of the piston.

1. A device for dispensing product in liquid form, comprising a fixedpart and a moving part, the fixed part including: an intake orifice anda delivery orifice, a body comprising a cavity, into which said orificesopen, said cavity being able to partially house the moving part, thevolume formed between the surface of the cavity and the moving partdefining an emptying chamber, the moving part able to partially move inthe cavity of the fixed part, including: a piston, a piston drivingelement, an axial spring, a duct extending along the circumference ofthe piston, such that said duct allows positions that allow fluidiccommunication between the emptying chamber and just one of said orificesand allows switchover positions in which all fluidic communicationbetween the emptying chamber and each of said orifices is forbidden, thedevice including a cam able to convert the rotation of the pistondriving element into an oscillatory-rotary movement of the piston,wherein the axial spring is able to absorb energy during a liquid intakephase and to restore same during a liquid delivery phase, said springbeing positioned around the piston which is on the moving part situatedin the cavity of the body.
 2. The device according to claim 1, whereinthe axial spring is a helical spring.
 3. The device according to claim1, wherein the duct is delimited by sealing lips in order to ensure thefluid-tightness between the piston and the body of the device.
 4. Thedevice according to claim 1, wherein the duct includes a delivery grooveconnecting the delivery orifice to the emptying chamber during thedelivery phase, and an intake groove connecting the intake orifice tothe emptying chamber during the intake phase.
 5. The device according toclaim 4, wherein the intake groove is in the form of a helical internalthreading forming an angle α preferably identical to the angle of theslope of the cam.
 6. The device according to claim 4, wherein thedelivery groove extends on an axis co-linear with that of the camabutment and forms with the longitudinal axis of the piston an angle βsuch that 0° ≤ β ≤ 70°.
 7. The device according to claim 6, wherein theangle β is preferably an angle of 0°.
 8. The device according to claim1, wherein the intake orifice and the delivery orifice are angularlyseparated by an angle between 170° and 190° on a plane perpendicular tothe longitudinal axis of the piston.
 9. A method for administering afluid using a device according to claim 1, including the following foursuccessive steps: a. An intake step, during which the device is actuatedto drive the rotation of said cam, in order to obtain anoscillatory-rotary movement of the piston; during saidoscillatory-rotary movement, the intake orifice is in communication withthe duct and the delivery orifice is covered so as to obtain the fillingof an emptying chamber and the compression of the axial spring betweenthe cam and a spring support, b. A first intermediate step, during whichthe two orifices, the intake orifice and delivery orifice, are coveredand non-communicating, and during which the emptying chamber is at itsmaximum volume, c. A delivery step, during which the axial spring isdecompressed in order to bring about the translation of the piston, inorder to empty the emptying chamber through the first delivery groove influidic communication with the delivery orifice, d. A secondintermediate step, during which the two orifices, the intake orifice andthe delivery orifice, are covered and non-communicating, the piston isat the end of the stroke in the cavity of the body of the fixed part,and the axial spring is released.
 10. The method according to claim 9,wherein the height of the abutment of the cam is adjustable in order tovary the liquid volume ejected from the emptying chamber through thedelivery orifice.
 11. A medical apparatus containing the deviceaccording to claim
 1. 12. A fluid cartridge including a fluid circuitand a dispensing device according to claim
 1. 13. A method foradministering a fluid using a medical apparatus containing the deviceaccording to claim 1.